Re: Procedure PR/PI question

[Alan Campin <alan0307d@xxxxxxxxx>]

The simplest way is to pass as a parameter to program inside your
procedure(Something we end up doing all the time because of legacy code).
Now is you are smart you won't do that but you might not be thinking that
day and somebody makes a change to that program and surprise your program
starts failing for unknown reasons in a procedure that has nothing to do
with the called program. The fact that you code it as CONST on the program
call prototype means absolutely nothing to the called program. It can
change anything it wants.


On Mon, Apr 29, 2013 at 3:16 PM, Rory Hewitt <rory.hewitt@xxxxxxxxx> wrote:

> Alan
>
>
> CONST means I will try to keep you from changing it but there are plenty of
> ways to change the variable inside the procedure and have the calling
> variable to be changed. These include passing as a parameter to a program
> inside the procedure, getting a pointer to it, putting in a data structure.
> The compiler may try to prevent you from changing but it is easy enough to
> change which could result in some really nasty bugs.
>
> I don't know if I'd agree that there are realistically "plenty of ways" to
> change it. I've never accidentally changed a CONST parameter, and I'm
> always surprised when people do so.
>
> Rory
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